#include<bits/stdc++.h>
using namespace std;
int n,i,j;
int main(){
    freopen("duel.in","r",stdin);
    freopen("duel.out","w",stdout);
    int min=9999999,b=0,c=0;
    cin>>n;
    int a[n];
    for(i = 0;i<n;i++){
        cin>>a[i];
    }
    int k[n];
    for(i = 0;i<n;i++){
        k[i]=a[i];
    }
    for(int y = 0;y<n;y++){
        for(i = 0;i<n;i++){
            if(a[i]<min&&k[i]>-1){
                min=a[i];
                  b=i;
            }
        }
        for(i = 1;i<999999;i++){
            for(j = 0;j<n;j++){
                if(min+i==a[j]&&k[j]>0){
                    k[j]=0;
                    k[b]=-1;
                    min=9999999;
                }
            }
        }
    }
    for(i = 0;i<n;i++){
        if(k[i]>-1){
            c++;
        }
    }
    cout<<c;
    return 0;

}
